It has been demonstrated that the prevalence of alcohol abuse and alcoholism varies widely among different ethnic groups. Asian populations appear to have lower rates of alcoholism than other ethnic groups, whereas certain tribes of Native Americans have very high rates of alcohol abuse. These differences in rates of alcoholism between various ethnic groups are thought to reflect a combination of sociocultural and biological factors. Several studies suggest that there may be racial and ethnic differences in biologic sensitivity to alcohol. The source of this disparity in alcohol sensitivity, while not well understood, presumably is the result of genetic differences in metabolic factors as well as differences in CNS "reactivity." This application proposes two studies which will evaluate reaction to alcohol in 21-25 year old Asian and Native American men. Subjects will be recruited and screened for personal and family history of alcoholism and other psychiatric disorders and will be genotyped for differences in alcohol metabolizing enzymes (ALDH2, ADH2, and ADH3 alleles). Subgroups of subjects will be identified based upon family history of alcoholism and genotyping variations. An alcohol/placebo challenge protocol will be used to evaluate behavioral, neuroendocrine, and electrophysiological reactivity to alcohol in matched subject subgroups. Subjects will also be followed over the course of the study to determine if they develop changes in alcohol drinking patterns or alcohol related problems. These studies have the potential to identify clinically relevant genetic markers of acute alcohol intoxication in addition to identifying possible cognitive, physiological, and/or neurochemical mechanisms which may be risk or protective factors for alcoholism or alcohol abuse.